The immunologists at this institution have sharpened a broad program in Immunologic Aspects of Cancer to a coherent and concise theme on Immunologic Resistance to Cancer. This multi-faceted approach toward a single goal encompasses the following broad sections with their collaborative projects. Mechanisms of control of lymphoid tumor growth evaluating: interaction of normal lymphoid cells as growth requirement of lymphoid tumors; suppressor cell induction by reticulum cell sarcoma; genetic control of resistance to murine plasmacytomas; immunosuppressive activity of mononuclear cells from plasmacytoma mice; and lymphocyte membrane components. Transfer factor characterization by means of rabbit antibody and isoelectric focusing; in vivo assay of TFd in human to BALB/c mouse and mouse to mouse transfer of CMI; effects of murine TFd on growth of SV tumors in BALB/c mice; and effects of human TFd on growth of human melanoma in NU/NU mice. Studies of cell-meditated immunity to solid tumors in human and in chicken models. The monocyte-macrophage system in resistance to tumors: studies of human macrophages in long-term culture; comparison and properties of monocytes from normals and cancer patients; studies of human monocyte in vitro killing of tumor cells. Role of antitumor immune complexes and complement in host defense in cancer patients.